SpaceX of California says it plans to launch the most powerful expendable rocket since the Apollo era in 2013.

The Falcon 9-Heavy is a beefed up version of the vehicle the company will soon use to send a robotic cargo ship to the International Space Station.

The new rocket should be capable of putting more than 53 tonnes (117,000lb) of payload in a low-Earth orbit - more than twice that of the space shuttle.

CEO Elon Musk said the rocket would be made safe enough to launch astronauts.

"It is designed to meet the Nasa human-rating standards," he said. "So, for example, it is designed to structural safety margins that are 40% above the actual flight loads it would expect to encounter."

The performance promised by the 70m-tall (227ft) rocket would make possible bigger, more ambitious missions beyond the space station, he added.

I just found this old thread which I started in 2011, and which went nowhere at the time. Thought I'd bump it up to the top, in view of today's phenomenally successful first launch of the Falcon Heavy. I watched the livestream of it on the SpaceX website a couple of hours ago, and I'm still awestruck. All I can say is, wow!